Airborne reflectors for satellite-based quantum entanglement and key distribution

Area of Science:

• Quantum communication
• Optical engineering
• Satellite technology

Background:

• Satellite quantum communication is hindered by signal loss over long distances.
• Factors like geometric loss and atmospheric attenuation reduce entanglement distribution and secret key rates.
• Direct satellite-to-ground links suffer performance degradation, especially at low elevation angles.

Purpose of the Study:

• To propose a practical solution for enhancing satellite-based quantum communication.
• To mitigate the effects of signal loss in long-distance quantum links.
• To improve entanglement distribution rates and extend secure communication windows.

Main Methods:

• Design and conceptualization of an airborne, gold-coated parabolic reflector.
• Placement of the reflector in the stratosphere above a ground station.
• Modeling the reflector as a virtual transmitter to augment the satellite link.

Main Results:

• A substantial increase in distributed entanglement rate, up to 25 times at zenith compared to direct communication.
• Reduced minimum elevation angles for secure communication (e.g., BB84: [Formula: see text] to [Formula: see text], E91: [Formula: see text] to [Formula: see text]).
• Extended communication time windows by [Formula: see text] for BB84 and [Formula: see text] for E91.

Conclusions:

• The airborne reflector offers a viable method to significantly enhance satellite quantum communication performance.
• The proposed approach overcomes limitations of direct satellite-to-ground links, particularly at lower elevation angles.
• This technology has the potential to extend the duration and reliability of secure quantum communication networks.